Báez made his professional debut in 2017 with the rookie–level Arizona League Padres, and after one start where he gave up two runs and struck out seven in five innings, was promoted to the Single–A Fort Wayne TinCaps where he finished the season, starting ten games, compiling a 6–2 record and 2.45 ERA with 82 strikeouts in 58+2⁄3 innings pitched.[3][4][5]
Following the 2017 season, Báez was rated as the Midwest League's No. 4 prospect according to Baseball America. He also earned Honorable Mention Starting Pitcher honors on the 2017 Yahoo Sports All-Minor League Team. Baez was ranked as the Padres' No. 7 prospect according to MLB.com prior to the 2018 season.[6] He spent the 2018 season with both the High–A Lake Elsinore Storm and the Double–A San Antonio Missions, going 4–10 with a 3.69 ERA in 21 total starts between both teams.[7]
Báez began 2019 with the Double–A Amarillo Sod Poodles,[8] going 3–2 with a 2.00 ERA over 27 innings. He was promoted to the major leagues on July 20, 2019.[9] He made his major league debut on July 23, pitching a scoreless inning of relief versus the New York Mets.[10] In 24 games for the Padres, Báez went 1–1 with a 3.03 ERA and 28 strikeouts over 29+2⁄3 innings. In 2020, Báez recorded a 7.71 ERA with 7 strikeouts and two walks in 4.2 innings of work across three games (1 start).[11]
On March 31, 2021, it was announced that Báez would require Tommy John surgery and miss the 2021 season.[12] On April 1, he was placed on the 60-day injured list.[13]
On June 6, 2022, Báez was activated off of the injured list and optioned to the Double-A San Antonio Missions.[14] Báez made two scoreless appearances for the Padres in 2022, spending the majority of the year in the minor leagues, where he recorded a 5-3 record and 4.91 ERA in 41 appearances.
Báez was optioned to the Triple-A El Paso Chihuahuas to begin the 2023 season.[15] He was designated for assignment on March 30 after Rougned Odor, David Dahl, and Domingo Tapia were added to the roster. [16] He cleared waivers and was sent outright to El Paso on April 3.[17] He made 32 appearances split between the rookie–level Arizona Complex League Padres, High–A Fort Wayne, Double–A San Antonio, and Triple–A El Paso, accumulating a combined 4–1 record and 6.64 ERA with 34 strikeouts across 40+2⁄3 innings pitched. Following the season on December 18, Báez was released by the Padres organization.[18]
